60%
<span class="questionum" style="background-color: transparent; color: rgb(0, 0, 0); float: left; quot;微软雅黑","helvetica neue","hiragino sans gb"; font-size: 14px; font-style: normal; font-variant: normal; font-weight: 100; letter-spacing: normal; line-height: 21px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; orphans: 2; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px; position: relative; text-align: left; text-decoration: none; text-indent: 0px; text-transform: none; top: 6px; -webkit-text-stroke-width: 0px; white-space: normal; word-spacing: 0px; z-index: 9;"><span style="display: inline !important; float: none; background-color: transparent; color: rgb(0, 0, 0); 微软雅黑","helvetica neue","hiragino sans gb"; font-size: 14px; font-style: normal; font-variant: normal; font-weight: 100; letter-spacing: normal; orphans: 2; text-align: left; text-decoration: none; text-indent: 0px; text-transform: none; -webkit-text-stroke-width: 0px; white-space: normal; word-spacing: 0px;"> <div class="q_content bianji_box" id="title" style="background-color: transparent; border-bottom-color: transparent; border-bottom-style: solid; border-bottom-width: 1px; border-image-outset: 0; border-image-repeat: stretch; border-image-slice: 100%; border-image-source: none; border-image-width: 1; border-left-color: transparent; border-left-style: solid; border-left-width: 1px; border-right-color: transparent; border-right-style: solid; border-right-width: 1px; border-top-color: transparent; border-top-style: solid; border-top-width: 1px; color: rgb(0, 0, 0); quot;微软雅黑","helvetica neue","hiragino sans gb"; font-size: 14px; font-style: normal; font-variant: normal; font-weight: 100; letter-spacing: normal; line-height: 21px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; min-height: 20px; orphans: 2; padding-bottom: 5px; padding-left: 5px; padding-right: 5px; padding-top: 5px; position: relative; right: 0px; text-align: left; text-decoration: none; text-indent: 0px; text-transform: none; top: 0px; -webkit-text-stroke-width: 0px; white-space: normal; word-spacing: 0px;" contenteditable="true" placeholder="题干，必填">本题考查的知识点是下沉式广场的防火检查。<div class="q_content bianji_box" id="title" style="background-color: transparent; border-bottom-color: transparent; border-bottom-style: solid; border-bottom-width: 1px; border-image-outset: 0; border-image-repeat: stretch; border-image-slice: 100%; border-image-source: none; border-image-width: 1; border-left-color: transparent; border-left-style: solid; border-left-width: 1px; border-right-color: transparent; border-right-style: solid; border-right-width: 1px; border-top-color: transparent; border-top-style: solid; border-top-width: 1px; color: rgb(0, 0, 0); quot;微软雅黑","helvetica neue","hiragino sans gb"; font-size: 14px; font-style: normal; font-variant: normal; font-weight: 100; letter-spacing: normal; line-height: 21px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; min-height: 20px; orphans: 2; padding-bottom: 5px; padding-left: 5px; padding-right: 5px; padding-top: 5px; position: relative; right: 0px; text-align: left; text-decoration: none; text-indent: 0px; text-transform: none; top: 0px; -webkit-text-stroke-width: 0px; white-space: normal; word-spacing: 0px;" contenteditable="true" placeholder="题干，必填">下沉式广场防风雨棚不得完全封闭，四周开口部位要均匀布置，开口的面积不得小于室外开敞空间地面面积的25%，开口高度不得小于1.0m；开口设置百叶时，百叶的有效排烟面积可按百叶通风口面积的60%设置。<div class="q_content bianji_box" id="title" style="background-color: transparent; border-bottom-color: transparent; border-bottom-style: solid; border-bottom-width: 1px; border-image-outset: 0; border-image-repeat: stretch; border-image-slice: 100%; border-image-source: none; border-image-width: 1; border-left-color: transparent; border-left-style: solid; border-left-width: 1px; border-right-color: transparent; border-right-style: solid; border-right-width: 1px; border-top-color: transparent; border-top-style: solid; border-top-width: 1px; color: rgb(0, 0, 0); quot;微软雅黑","helvetica neue","hiragino sans gb"; font-size: 14px; font-style: normal; font-variant: normal; font-weight: 100; letter-spacing: normal; line-height: 21px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; min-height: 20px; orphans: 2; padding-bottom: 5px; padding-left: 5px; padding-right: 5px; padding-top: 5px; position: relative; right: 0px; text-align: left; text-decoration: none; text-indent: 0px; text-transform: none; top: 0px; -webkit-text-stroke-width: 0px; white-space: normal; word-spacing: 0px;" contenteditable="true" placeholder="题干，必填">本题答案：。